Electrical apparatus



Feb. 23, 1932. 1 A, M. PHELAN ET AL 1,847,033

ELECTRICAL APPARATUS 4 Sheets-Sheet 1 Filed March 17, 1922 Fig. 6,

fiz/eizfams; 144}; a 717 J M9 m L. A M. PHELAN ET AL ELECTR I CAL APPARATUS Feb. 23, 1932.

Filed March 17. 1922 4 Sheets-Sheet 2 I/Z/e/Z 20/19. a,

M fw J 1932. I L A. M. PHELAN ET AL 1,847,033

ELECTRICAL APPARATUS File Mar h 17. 192 4 Sheets-Sheet 3 Feb. 23, 1932.

L. A. M PHELAN ET AL ELECTRI CAL APPARATUS Filed March 17, 1922 4 Sheets-Sheet 4 Patented Feb. '23, 1932 LOUIS A. H. PHELAN' AND CLIFFORD HOTC BY DIRECT AND MISNE'ASSIGNMEN'I'S, TO

musacr BELOIT, wrsconsnr, assrenons,

MINNEAPOLIS-HONEYWELL REGULATOR COMPANY, OF MINNEAPOLIS, MINNESOTA, A CORPORATION OF DIELAVTAIB'E ELECTRICAL arram'rus Application am March 17,

Our invention relates to electric apparatus and it has special reference to electric switching devices which may be actuated to control electric circuits at the expenditure of very small quantities of energy, such. as'may be available in a heat responsive element or thermostat when subjected to temperature changes through a substantially narrow rillfifee ore particularly, our invention pertains to a thermostatically operated electric switch which comprises a heat responsive element or thermostat that actuates an electric switching mechanism for opening and closing an electric circuit as the thermostat expands [and contracts by reason of the temperature changes that may influence it..

Our present invention refers to electric switches of the character defined wherein the cooperating contactmembers or electrodes between which the electric circuit is made and broken, are fixed in position and. stationary relative to one another and are adapted to 'be bridged by a conducting body that is moved to and fro by an actuating thermostat at the expense of very little energy, such as may be available when a temperature change of a few degrees only, or even of one degree, may occur. The cooperating contact members of our switching device are spaced suitable distances from one another to preclude premature electric discharges between them and they are completely enclosed in a sealed container thereby insuring them against corrosion, contamination and deterioration.

In the .electric switching devices of our present invention, we perform the switching operations, that are necessitated by the opening and closing of the associated electric circuit, through the intermediary of an electric contactor thaccomprises. a sealed container having cooperating contact members or electrodes sealed therein and which are adapted to be bridged and brought into conducting relation with one another through the agency of a body of mercury, likewise contained Within the container. The contactor which we employ is adapted for commercial installations and, as a consequence, handles appreciable quantities of current at any of the 1922. Serial No. 544,589.

standard voltages. The contactor is actuated by a thermostatic element and its position with reference thereto is rotatably adJuStable so that, if desired, the switching operations may be effected throughout a wide range of temperature variations which directly affect the thermostatic element that, in turn, actuates the contactor. The contactor is 50- des1gned and mounted that a very small movement only is required of it in order to perform its switching functions. Again, the thermostatic element actuating the contactor is so designed and mounted as to insure uniformity of operation and, at the same time, to develop suflicient energy, even throu hout small ranges of temperature changes, or actuating the contactor. These features of our invention are accomplished by. properly associating the thermostatic element or actuator and the contactor so that they may be rotated relatively to each other.

- An object, therefore, of our invention is to provide a thermostatically operated electric switch which will operate with certainty and accuracy to open and close commercial electrical circuits at the expenditure of a very small quantity of energy, such as that which is available through the medium of a thermostatic element when subjected to a very small range of temperature change. By reason of the very few parts employed in the devices of our present invention, no adjustments of any consequence are required after the initial setting thereof, and-the adjustments so made will be retained indefinitely, since there is no deterioration, corrosion or contamination of the electrical contact. members or electrodes which are adapted to handle substantially large quantities of electric current at any of the standard voltages.

Another object of our invention is to provide thermostatically operated electric switches of the character indicated above which will be simple and economical to construct and which will be substantially devoid of operating parts that are likely to deteriorate in any of the usual atmospheres obtaining in manufacturing plants, central stations and other places where our devices are likely to be installed.

Other objects of our invention will appear from the detailed description forming a part of this specification, and from the drawings to which reference may now be had for a better understandin of the scope and characteristic features 0 our invent1on.,

Figure 1 is a front elevational view of a thermostatically 0 erated electric switch embodying a form 0 our invention and having portions of its front casing, the graduated dial and thecontactor tube broken away in order that the device may be more clearly shown;

Fig. 2 is a cross-sectional view taken along the line 2-2 of Fig. 1;

Fig. 3 is a bottom view showing a portion of the device of Figs. 1 and 2;

Fig. 4 is a front view of a modified form of thermostatically operated electric switch embodying a form of our invention;

Fig. 5 is a cross-sectional view taken along the line 5--5 of Fig. 4;

Fig. 6 isa cross-sectional view taken along the line 6-6 of Fig. 5;

Fig. 7 is a plan view of a thermostatically operated electric switch embodying a form of our invention and having a portion of the cover broken away to show the interior of the housing inclosing the contactor;

Fig. 8 is a longitudinal cross-sectional view. of the device shown in Fig. 7 which is gaken7 along a plane passing through 88 of Fig. 9 is a cross-sectional view taken along the line 9-9 of Fig. 8;

Fig. 10 is a plan view of an assembled structure embodying our invention and showing a mounting for a thermostatic element in conjunction with a contactor;

Fig. 11 is a cross-sectional view taken alon the line 11-11 of Fig. 10, showing, in detail; a non-friction bearing construction for the holder which receives the contactor of Fig. 10; and

Fi 12 is a view of a modified form of nonriction hearing which supports a holder for the contactor.

The device illustrated in Figs. 1, 2 and 3 is particularly adapted for exposing its thermostatic element to convection heat currents and, as a consequence, we will designate this form of thermostatically operated electric switch as a convection-type switch. Upon an insulating plate 1 a thermostatic element 2 is mounted which comprises a re-, silient coiled bimetallic ribbon wound, in this instance and for the purpose of illustration only, in the form of a spiral. The ribbon from which the thermostatic element 2 may be constructed is shown as comprising two conducting strips 3 and 4 that are welded together or secured to each other in any suitable fashion and may, for example, be a German silver strip and a copper strip that have d1fi'erent coefficients of expansion. The outer mounted sleeve 9 which enga es a shaft 10 that projects through the insu ating plate 1, as shown in Fig. 2.

The outer end of the shaftlO is provided with a threaded extension that is received in a countersunk portion 11 formed in the rear of the plate 1 and that is secured in position by means of nuts 12. The sleeve 9 is rotatably mounted upon the shaft 10 and is prevented from moving longitudinally thereof by means of a set screw 13 which extends through the sleeve 9 and has its inner end slidingly received in a groove 14 formed in the shaft 10. The outer end of the sleeve 9 is provided with an extension 15 which is received in a hollow member 16 that is adapted to be rotated-by the sleeve 9. A' plate 17 having its front face graduated, as shown in Fig. 1, is provided with a central opening in which the sleeve 16 is journaled. The plate 17 is likewise mounted upon the bracket 7 and is held in fixed position by means of screws 18 which secure the plate to the bracket. It will be observed that the sleeve 16 receives a holder 19 which is removably positioned in said sleeve 16 by means of a connection 20, which eventuates a frictional connection between the actuating sleeve 16 and the holder 19. Because of said frictional connection between said actuator and said holder 19, relative movement therebetween is permitted whereby one of said members may be held still While the other member is rotatably moved with respect thereto.

From the foregoing description, it is apparent that the spiral thermostatic element 2 has its outer end secured in fixed position and that its inner end operates to rotate the sleeve 9 and, in conjunction therewith, the sleeve 16 wherein the holder 19 is received. The holder 19 comprises a spring clip 21 in which an elecgrical contactor 22 is received, as shown in The electrical contactor 22 comprises a sealed container 23, preferably a glass tube, in which cooperating electrodes 24 and 25 are sealed. The container 23 is evacuated and contains a body of mercury 26, as well as an inert gas. The container 23 is of tubular form, having its longitudinal axis placed approximately horizontally. The electrodes or contact members 24 and 25 may be made of pure metal which may be electrolytic iron and are disposed on one side of the axis of rotation of the holder 19. The body of mercury 26 rides on the lower inner surface of the container 23 and, when in the position shown in Fig. 1, serves to establish an electric circuit between the electrodes 24 and 25. When the contactor 22 is tilted in a direction opposite o that shown in Fig. 1, the mercury 26 flows -ner, the

to the other end ofthe container 23 andtheres by opens the electric circuit between the coprecluding the leadin -in.wire 27 from being exposed interiorly of t e container 23. Similarly, the electrode 24 is connected-to a leading-in wire 29 that is likewise imbedded in a glass shank 30. The electrodes 24 and 25, bemg fixed and stati'onar with respect to each other, are connected to exible leads 31and 32, respectivel as shownbest in Fi 3.

The flexible-leads are soldere to the lead ing-in wires and are severally threaded zhrough a rubber cushioning member 33 which encircles the contactor 22 where it is embraced by the cli 21 of the holder 19. In this manexible leads are extended from-the contactor 22 at substantially its axis of rotation. .As a result, the flexible leads 31 and 32 I do not impede or hinder tilting movements that may be imparted to the contactor 22 by the thermostatic element 2. This, therefore, insures that substantially all the energy available from the thermostatic element 2 1s utilized for tilting the contactor 22 and none of it is wasted in overcomim the rigidity that may be offered by the flexible leads 31 and 32. The flexible leads 31 and 32 are connected, respectively, to binding posts 33a and 34 which are mounted at the lower portion of the insulating plate 1. The binding posts 33a and 34 are also provided with apertures 35 and 36,

respectively, in which electrical conductors may be received that may pass through a bracket 37 and an opening 38, in alinement with said bracket, which is formed in the cover member 39 of the thermostatic electric switch.

The cover member 39 is a perforated casing, as shown in Fig. 2 and is secured to the mounting plate 1 by means of bolts terminating in thumb screws 40 and 41. The perforated cover or casing 39 allows the air to come into intimate contact with the thermostatic element 2 and thus the temperature changes occurring in this air influence the thermostatic element 2 accordingly, thereby, causing it to actuate the electrical contactor 22 which erforms the switching functions of the device. It will be noted that the cooperating electrodes or contact members 24 and 25 are fixed in position within the contactor tube 23 and that the electrical switching operations are performed through the agency of a body of mercury 26, placing said electrodes in conducting relation with each other or breaking the electrical circuit between said electrodes.

The graduated dial 17 and pointer 42 may be employed for indicating the degree of rotatable movement between the thermostatic coil 2 and the holder 19. The

element and sleeve 16 rotated with respect thereto, all because of the frictional connection between said holder 19 and said element 2. As a result, the position of the contactor 22 maybe varied, as desired, with reference to the thermostatic element 2. The device of Figs. 1, 2 and 3, .which we have desi nated as a convection type of thermostatically operated electric switch, is adapted for use in cooling chambers, drying rooms or ovens, and may be employed for regulating the temperature of refrigerating chambers and the like, and also for temperature alarms in connection with electrical machinery, firealarm devices, etc.

Reference may now be had to Figs. 4, 5 and 6, wherein are illustrated thermostaticaliy operated electrical switches which we will designate as. the contact type. The mechanism-illustrated herein comprises a metallic enclosing casing 45 having a smooth back wall 46 which terminates in an encircling flan e 47. Circumferentiall elongated oies 48 are formed in t e an e 47 and allow the casing 45 to be adjustab y mounted upon, and in close contact with, the tank or other device whose temperature changes are to be utilized in influencing the thermostatic element incorporated in this contact-type switch. In the present modification of the device incorporating a form of our invention, the spirally-coiled thermostatic element 2 has its outer end secured in fixed position by screwing it to a bracket 49 that is mounted on the back plate of the casing 46. The innercnd of the thermostatic element 2 is secured to a rotatably mounted sleeve 50 that is supported and journaled upon a pin 51 which serves as one bearing therefor. The other end of the sleeve 50 is journaled in a face plate 52, which may be graduated as shown in Fig. 4.

The thermostatic element 2 is enclosed in a chamber 53 having a front closure plate 54. Upon this front closure plate 54, the face plate 52 is mounted. A holder 55, which is removably mounted in the rotatable sleeve 50, receives the contactor 22 through which the electrical switching operations are performed. The electrical contactor 22 of Figs. 4 and '5 may be of the same construction as the contactor of Figs. 1, 2 and 3, and, as a s aced of the conduction of heat to sure plate 54, and as its front wall, a. glass panel 57 that is held in position by an annular member 58 which is screwed to the casing 45. The flexible leads 31 and 32 are brought from the casing 45 through bushings 59 in which the flexible leads are sealed.

From the foregoing description, it will be apparent that the thermostatic element 2 is housed in a closed chamber immediately adjacent to the back plate 46 of the casing 45. In this manner, the thermostatic element 2 is brought into close relationship with the de vice to which the casing 45 is secured and the temperature changes of which are employed for actuating the thermostatic element 2 and, in turn, the contactor 22. The contactor 22 is likewise contained within a closed chamber 56. The device of Figs. 4, 5, and 6 may, in some instances, be utilized for regulating internal temperatures of a tank by being attached in close contact with the tank. The device is adapted to be clamped tightly to the exterior surface of the tank or other member the temperature of which is being controlled, and is under the influence of temperature changes occurring within the tank by reason the thermostatic element 2 through the wall of the tank and the metallic back-plate 46 of the casing 45.

Referring to Figs. 7, 8 and 9, there is shown a thermostatically operated electric switch which we will designate as being of the immersion type. In this modification of our invention, an elongated spiral or helically coiled thermostatic element 60 is enclosed in" a tubular housing 61 which is sealed and sweated into an exteriorly threaded nipple 61a. The thermostatic coil 60 forms a helix of substantial length which is housed in the elongated extension 61, the walls of which are spaced only a slight distance from the coil 60 in order that the coil 60 may be brought into close relationship with the temperature of the fluid in which the tubular member 61 may be inn mersed. The lower end of the helical coil 60 is secured to a head 62 into which a centrally disposed longitudinally extending rod 63 terminates at its lower end. The upper end of the helical coil 60 is secured in fixed position by being welded or otherwise attached toa bracket 64 mounted on the inner side of a fixed face plate 65.- The upper end of the rod 63 is received in a rotatable sleeve 66 that is journaled in the face plate 65. The exposed surface of the face plate 65 may be graduated as shown in Fig. 7. The holder 19 is removably ositioned in the rotatable sleeve 66 and rotatalily mounted with respect thereto because of the aforementioned frictional connection and, as hereinbefore explained, receives the contactor 22 from which the flexible leads 31 and 32 extend to binding posts 67 and 68, respectively, which are mounted on the rear face 69 of an enclosing casing 70. Leads 71 and 72 extend from the binding posts 67 and 68,-respectively, for connecting the electrical'contactor 22 in an external electrical circuit. A cover 71a is removably mounted upon the casin by means of thumb screws 7 2a. The en arged view of Fig.

9 shows the relative positions of the central actuating rod 63, the thermostatic element 60,

which surrounds the rod 63, and the tubular housing 61 which encloses both of the aforesaid elements and permits them to be brought into close contact with the liquid or other material in which the thermostatic element 60 is to be immersed for controlling the temperature.

The housing 61 is to be placed horizontally in the tank or other containing vessel and a tight joint is efiected between the vessel in question and the switching mechanism by means of the ni ple 61a. The immersion type device of Figs.%, 8 and 9 may be used in connection with brine tanks, kettles, hot or cold chambers, stills employed in the manufacture of oil and other substances, plating tanks and the like.

In Figs. 10, 11 and 12, we have shown a modified form of thermostatically operated electric switch that comprises a few numbers of parts only which may be readily assembled and mounted. Moreover, we have shown in detail two forms of non-friction bearings for mounting the contactor 22 which are very simple and rugged in construction and, at the same time, are very sensitive in operation. A supporting member 75 is provided "at one of its ends with a lateral extension 76 to which the outer end of the spirally coiled thermostatic element 2 is secured by means of a screw bolt 77. The center of the spirally-coiled thermostatic element 2 subtends the other end of the supporting member 75 through which the threaded shank of a screw bolt 78 extends. A rotatably mounted sleeve 79 embraces the threaded shank of the bolt 78 which is secured in a support 75 by means of a nut 80. The head 81 of the bolt 78 is received in a countersunk portion 82 formed in the outer end of the sleeve 79. The inner end of the spirallycoiled thermostatic element 2 is secured at 83 by welding or solderin or any other suitable means to the rotata le sleeve 79. The inner end of the sleeve 7 9 is chamfered as shown at 84 in order that it will have a line contact only operating against the front face of the supporting member 75. The member 79 is made of phosphor bronze and its bearing surface rides upon the outer edges of the screw threads formed upon the bolt 78. As a consequence, the sensitiveness of the device is greatly enhanced and very little energy is required to rotate the sleeve 79, this energy being available, of course, through the contraction and expansionof the thermostatic element 2. A clip 85 is mounted on the outer end of the sleeve 79 and in it Ill ' engaging means 86a secured to the holder 85.

The plug 86a is of the same general type as shown in Figs. 2, 5 and 8 and permits the holder, with the contactor 22, to be removably positioned in the rotatable sleeve and, at the same time, allows of relative rota tion between the actuator and the contactor, all due to the frictional engagement between, these two elements.

While we have shown and describedseveral embodiments of our invention, it is to be understood that many modifications may be made therein without departing from the spirit and scope of the appended claims, and We desire that only such limitations shall be imposed upon our] invention as are specifically pointed out in the claims and such as are re- "quired by the prior art.

What we claim as new and desire to secure. by Letters Patent of the United States is:

1. A thermostatically operated electric switch comprising a mounting member, a

coiled thermostatic element having one of its ends attached to said mounting member, a rotatably mounted holder to which the other end of said thermostatic element is connected whereby said holder may be rotatedin either direction as said thermo static element expands and contracts, an electrical contactor mounted upon said holder, and yielding frictional slip engaging means permitting when desired of relative movement of said contactor with reference to said thermostatic clement, said contactor comprising a container, electrodes sealed therein, leads extending from said electrodes for connecting them in an external electric circuit, and a movable conducting body in said container.

2. A thermostatically operated electric switch comprising a mounting member,-a coiled thermostatic element having one of its ends attached to said mounting member, a rotatable holder to which the other end of said thermostatic element is connected whereby said holder may be rotated in either direction by said thermostatic, element, an

.;electric-co'ntactor mounted upon said holder,

and ielding frictional slip engaging means enab ing rotatable movement of said contactor relative to said thermostatic element, said 'contactor comprising a container, electrodes sealed therein, flexible leads extending from said electrodes for connecting them in an external electric circuit, and a movable body of mercury in said container for making and breaking the electric circuit between said electrodes.

3. A thermostatically operated electric switch comprising a coiled thermostatic element having one of its ends relatively stationary, a. rotatable member to which the other end of said thermostatic element is "connected whereby said member may be r0- tated in either direction as said thermostaticcIement expands and contracts, a holder yielding frictional slip engaging means permitting said holder to be moved rotatably relative to said member, and an electric contactor mounted on said holder comprisin a container, electrodes sealed therein, flexi le leads extending from said electrodes for connecting them in an external electric circuit, and a movable body of mercury in said container for making and breaking the associated electric circuit between said electrodes. I

4. A thermostatically operated electric switch comprising a mounting member, a coiled thermostatic element having one of its ends-attached to said mounting member, a rotatably mounted holder, means for connecting said holder to the other end' of said thermostatic element whereby said holder may be rotated in either direction as said thermostatic element expands and contracts, an electric cont-actor mounted upon said holder, said contactor comprising a container, spaced electrodes sealed therein, and a conducting body for making and breaking an electric circuit between said electrodes, and yielding frictional slip engaging means permittin of relative rotative movement between sai holder and said means connecting said holder to said thermostatic element.

5. A thermostatically operated electric switch comprising amounting member, a coiled thermostatic element having one of its ends attached to said mounting member a rotatable member disposed centrally of said coiled thermostatic element and connected to the other end thereof whereby said rotatable member may be rotated in either direction, a contactor connected to said rotatable member, said contactor comprising spaced cooperating electrodes and a conducting member for making and breaking the circuit between said electrodes as said thermostatic element expands and contracts, and yielding frictional slip engaging means enabling of rotatable movement of said contactor relative to said coiled thermostatic element.

6. A --.thermostatically operated electric switch comprising a mounting member, a coiled resilient thermostatic element having one of its ends attached to said mounting member, a rotatable member disposed centrally of said coiled element the other end of which is connected to said rotatable member to rotate it in either direction, an electric contactor connected to said rotatable member, and a yielding frictional slip connection permitting of rotatable movement of said contactor with respect to said coiled element, said contactor comprising a container, fixed cooperating electrodes sealed therein, flexible leads for connectin said electrodes to an external electric circuit, and a body of mercury in said container for making and breaking the electric circuit between said electrodes.

7. A thermostatically operated electric switch comprising a mounting member, a coiled thermostatic element having one end attached to said mounting member, a rotatable member supported on said mounting member and centrally of said thermostatic element the other end of which is secured to said rotatable member, a holder connected to said rotatable member, and an electric contactor mounted on said holder, said contactor comprising a sealed container, coopcrating and spaced electrodes sealed therein and disposed on the same side of the axis of rotation of said rotatable member, a body of mercury Within said container, and flexible leads for connecting said electrodes to an external electric circuit, said flexible leads extending from said contactor and said holder at points in proximity to the axis of rotation of said rotatable member.

8. An electric switch comprising an actuator, an electrical contactor connected to said actuator whereby the contactor may be rotated by said actuator in either direction, and yielding continuously acting frictional slip engaging means for permitting, when desired, of relative movement of said contactor with respect to said actuator, said contactor comprising a container, spaced electrodes sealed therein, leads extending.from said electrodes for connecting them in an external electric circuit, and a movable body of mercury in said container.

9. An electric switch comprising an actuator, a holder connected thereto which may be rotated by said actuator in either direction, an electrical contact'or mounted in said holder, and frictional slip connecting means between said holder and said actuator permitting, when desired, of relative movement of said holder with respect to said actuator but said connecting means at all times maintaining said contactor in any position that it may assume through the action of said actuator, said contactor comprising a container, spaced electrodes sealed therein, leads extending from said electrodes for connecting them in an external electric circuit, and a movable body of mercury in said container.

10. A thermostatically operated electric switch comprising a thermostatic element having one of its ends relatively stationary,

said electrodes for connecting them in an external electric circuit, and a movable body of mercury in said container.

11. In a glass tilting electrical contactor tube, lead wires for said tube, common means for retaining said tube and for positioning said Wires in respect to the tilting axis of said' tube comprising a band surrounding said tube and slits in said band into which said wires are drawn and secured.

12. In a contactor tube, lead wires for said tube, common means for retaining said tube and for positioning said wires in respect to 'an axis of said tube, com rising a band covering a portion of said tu e and holes in said band through which said wires are drawn.

- 13.. In a tilting electrical contactor tube, lead wires for said tube, common means for supporting said tube and for positioning said wires in respect to the tilting axis of said tube comprising a band surrounding the middle portion of said tube, and slits in said band into which said leads are drawn and secured.

14.. In a contactor tube, lead wires for said tube, common means for retaining said tube and for positioning said wires in respect to an axis of said tube, comprising a band coverin a portion of said tube and holes in said loan through which said wires are drawn and clamping means engaging said band for supporting said tube.

15. In a glass tilting electrical contactor tube, lead wires extending out from said tube at points remote from the tilting axis of said tube, common means for retaining said tube and for positioning said wires in respect to the tilting axis of said tube comprising a band and pivoted clamping means engaging said band for supporting said tube.

16. In a contactor tube having wires issuing from substantially the ends thereof, means for positioning said Wires in respect to an axis of the tube comprising a band surrounding the middle portion of said tube and slits in said band into which said leads are drawn and secured.

17. A thermostatically operated electric switch comprising a thermostatic element having one of its ends attached to a mounting member, a holder mounted to be moved in opposite directions by said thermostatic element, a contactor mounted upon said holder, and a frictional slip connection permitting of relative movement between said holder and said thermostatic element but said connection at all times maintaining said contactor in any position it may assume through the action of said thermostatic element, said contactor comprisin a container, electrodes in opposite directions as said thermostatic element expands and contracts, an electric switching means mounted upon said member, and yielding contlnuously acting frictional v slip means whereby said member may be moved relativel tov said thermostatic element, said electric switching means constituting a contactor comprising a container, electrodes sealed therein, leads extending from said electrodes for connecting them in an external electric circuit, and a movable conductor in said container controlling the electric circuit through said electrodes.

19. A thermostatically operated electric switch comprising a casing, a helically coiled thermostatic element projecting therefrom and having one of its ends secured to said casing, a member having one of its ends connected to the other end of said thermostatic element and the other end of said member being accessible interiorly of said casing, said thermostatic element as it expands and contracts serving to move said member, a tiltably mounted contactor in said casin and adapted to be tilted in either direction by said member, and frictional slip means housed in said casing and permitting relative movement between said contactor and said member.

20. A thermostatically operated electric switch comprising a casing, a helically coiled thermostatic element projecting therefrom and having one of its ends stationary and secured to said casing, a rotatably mounted member connected to the other end of said thermostatic element and adapted to be actuated thereby as said thermostatic element expands aiid contracts, said member being accessible interiorly of said casing, a tiltable contactor housed in said casing and adapted to be tilted in either direction by said member whereby an external electric circuit may be made and broken, and frictional slip means housed in said casing and permitting relative movement between saidcontactor and said member.

21. A thermostatically operated electric switch comprising a casing, 21 helically coiled thermostatic element projecting therefrom and having one of its ends stationary and secured to said casing, a rotatably mounted member extending axially of said thermostatic element and adapted to be actuated by the other end of, said thermostatic element whereby said member may be rotated in either direction as said thermostatic element expands and contracts, an electric switching means mounted in said casing and adapted to be operated by said member, and frictional slip engaging means housed in said casing and permitting relative movement between sbaaid electric switching means and said mem- 22. In a device of the class described, in combination, a thermal member sensitive to temperature changes, an electrical contactor actuated thereby, said contactor comprising a container, electrodes sealed therein, con

ductors attached to said electrodes for conmeeting them in an electric circuit, and a movable conductor in said container for making and breaking an electric circuit between said electrodes, and yielding continuously acting frictional slip'connecting means between said thermal member and said contactor enabling relative movement therebetween. I

23. The combination with an electric circuit including a contactor that comprises a container, electrodes sealed therein, conductors attached to said electrodes for connecting themin the electric circuit, and a movable conductorin said container for making and breaking the electric circuit between said electrodes, of a thermostatic control for said contactor including a thermal member, and yielding continuously acting frictional slip connecting means between said thermal mem- K ber and said contactor for permitting of relative movement therebetween. I

24. In an electric .switch, the combination with an actuator, and a contactor controlled thereby to make or break an electric circuit,

said contactor comprising a container, electrodes therein, a movable conducting member to control circuit connections between said electrodes, and conductors for connecting said electrodes in the electric circuit, of a continuously acting frictional slip connecting means between said actuator and said contactor whereby relative movement is permitted therebetween.

25. A thermostatically operated electric switch comprising a coiled thermostatic element having a plurality of convolutions, a supporting member to which one end of said element is fastened, and a contactor secured to the other end and positionedsubstantiallycentrally of said coiled element, said contactor being actuated to control an electric circuit by the movements occasioned by the temperature variations of said element and" said contactor comprising an enclosed tube, spaced electrodes therein, and a conducting body movable therebetween.

26. In combination with a mercury electric switch comprising an elongated container, of flexible conductor leads for said switch, and

- ible leads being held by said member where by they extend from said container in proximity to the tilting axis of said electric switch.

28. In a contactor tube, flexible lead wires therefor, and common means for retaining said contactor tube and for positioning said flexible lead wires, said common means comprising a member embracing said contactor tube and engaging said flexible lead wires so that they project from said contactor tube in priximity to an axis thereof.

29. An electric switch comprising a casing, electric switching means housed in said casing, a thermally responsive device supported upon and pro ecting outwardly from said casing and being sensitive to temperature changes normally occurring exteriorly of said casing for operating said electric switching means, and frictional slip engaging means permitting of relative movement between said electric switching means and said device.

30. An electric switch comprising a casing, electric switching means housed in said cas ing, a thermal member supported upon and projecting outwardly from said casing and being sensitive to temperature changes normally occurring exteriorly of said casing, a second member accessible interiorly of said casing and actuated by said thermal member for controlling the operation of said electric switching means, and frictional slip engaging means permitting of relative movement between said switching means and said sec" ond member.

31. In an electric switch, a casing, atilt able mercury contactor within said casing, a tubular member ri idly secured to said casing and extending laterally therefrom, their" 'mostatic actuating means disposed adjacent one end of said tubular member and in axial alignment therewith, and yielding continuously engaging slip connection means connecting said actuating means and said contactor.

32. In an electrical switch, a casing, a tiltable mercury contactor within said casing, a member rigidly secured to said casing and extending laterally therefrom, thermostatic actuating means disposed adjacent the end of said laterally extending member, and yielding continuously engaging slipconnection means connecting sald actuating means and said contactor said actuating means being exposed to render it accessible for the purpose of subjecting it to heating zones to which said switch is not exposed.

In witness whereof, we have hereunto subscribed our names. 1

LUUIS A. M. PH'ELAN. 'CLIFFORD HQTCHKISS. 

